Numerous of today's wells related to the production of hydrocarbons are completed with permanently installed monitoring devices for measuring data such as pressure, temperature, flow rate, flow composition, flow direction, sand and other. In addition, many wells are completed with permanently installed instrumentation and devices in order to enable both remote monitoring and control of that well, eliminating the need for any well intervention. The control devices comprise means for controlling influx of produced fluids (and the out flux of injected fluids) such as valves, sliding sleeves, downhole chokes and similar. Wells that include permanent systems for remote monitoring and control are often referred to as intelligent completions.
In relation to this, communication is becoming a very vital concept in borehole instrumentation systems. The systems that are being developed consist of a number of different devices, where each device typically is capable of executing one specific task. If these devices are to work properly together, they must be able to communicate with each other. To do this, they must be physically connected and, equally important, they must speak a common language. Particularly in monitoring and controlling well production there is a need for transmitting data and commands in any direction along a wellbore completion. For example is there a need for transmitting measurement data from the wellbore to the surface, there may be a need for transmitting commands to tools in the well, or instruments located in different locations in the wellbore may need to exchange information.